Automatic alarm system



2 Sheets-Sheet l H. T. NICOU AUTOMATIC ALARM SYSTEM Filed Jan. 13, 1938Aug. 25, 1942.

fi m \m T \Q Q Q F 1 m .u m k PM VJ M H w N L 3 u M w w 5, 1942. H. T.NlCOU AUTOMATIC ALARM SYSTEM Filed Jan. 13, 1938 2 Sheets-Sheet? J J 5 mQ F Q M t \QQ\ w m n F n m n QM U .Q. E EHMEE: u. U fi w V E @IL {IL [ILan F Q MIT III 3Q Q \Q \Q Q b uHnw w w b J \hv x\ \B Q w .l T u u G iv AQ R v m Q Q u H W Patented Aug. 25, 1942 UN ETE' STATES ATENT ()FFICEApplication January 13, 1938, Serial No. 184,892 In Sweden January 20,1937 4 Claims.

This invention refers to automatic alarm systems having one or morecontrol circuits, sections or loops connected to a source of current,such as a battery, and normally closed, each section being. providedwith means, such as circuitbreakers, for breaking the circuit in case offire or other danger. Thesecircuit-breakers are arranged in thelocalities to be watched over through which said section or sections aredrawn.

The chief object vof this invention is tocreate an automatic alarmsystem which may be built and operated at low costs but nevertheless issafe in operation and very reliable.

Another object of this invention is to simplify the construction ofelectric alarm systems, without reducing their reliability and safety ofoperation. In particular, the raising of alarm shall be secured alsounder unfavourable conditions.

Another object of this invention is torender it possible to increase thenumber of circuitbreakers, thermo-contacts or fuses to be used in eachsection, while still retaining a high selectivity and rendering iteasytolocalize a fault or a fire.

Another object of this invention is to render it possible to localizethe position of a fault or a danger, such as a fire, more accurately andmore rapidly than heretofore.

Another object of this invention is to give an automatic and reliableindication of the position of a fault or a danger, by simple andinexpensive means.

Another object of this invention is to reduce the length of the wiresnecessary for the control circuits or sections, without reducing thereliability and the safety. Thus, the system will be less expensive andalso less exposed to line faults and fault signals.

Other objects will be evident frorn'the following specification andclaims.

Embodiments of the invention are illustrated in the annexed drawings.

Fig. 1 shows an electric alarm system in accordance with this invention.

Fig. 2-shows a modification.

Referring now to Fig. 1 of the drawings, I and II indicate two controlcircuits, sections or loops drawn through the localities to be watchedover. It is understood that the number of sections is arbitrary, thoughonly two sections are shown for the sake of clearness. In'some-cases onesingle section may be used. Each section comprises two conductors orwires 11, b and a number of circuit-breakers, thermo-contacts or fusesT, it

being. understood that multiple-wires sections may also be used.The-parts below the dash-anddot-line C-C are arranged in' acentral post.

The branch or wire I) of section I has one end connected with the+pole-of a central battery B via the winding .of a section relay Rb andthe normally closed contact bv of that *relaywhich is normally energizedlike all the section relays. The other end of that wireis connected withan inner point of the battery B at the'tapi Ill-via the normally closedcontact-19h of the'relay Rb. To that same tap l 0 one end of the wire aof section I is connected via the windingqof section relay R9. and thenormally closed contact an of that relay. The opposite end of the samewire a is connected with the pole of the-battery B via the normallyclosed contact av of the relay Ra and the small protective resistance m.

The wires of section II and the other sections,

if any, are connected to the battery taps-in quite similar manner. Thesection relays of'section II are indicated by Rnb' and Rm.

The contacts av, ah, bv, bh are double, the-upper contact of each pairbeing normally closed while the lower one is normally open.

Two milliamperemeters 'Av, Ah are provided, each connected in serieswith a battery B1 and'Bz. These amperemeters are connected with thenormally open contacts of the'pairs av, ah, bv, bh. vThe right-handammeter Ah is connected with one such contact at bh andanother at an ofthe relays Ra, Rb of section I and also with the same contacts of therelays Rm, RIIb of section II etc. Similarly, the left-hand ammeter Avis connected with the normally open contacts av, bv'of the sections.Taps for connecting further sections to the ammeters are shown at 8.

In the embodiment as shown in Fig. 1 the milliamperemeters Av, Ah arecommon to all'sections, while each section has its individual sectionrelays Ra, Rb, RIIa,RIIb.

Two preferred embodiments of thermocontacts or fuses are shown in detailand on a larger scale in section I.

In'the left-handthermocontact T of section I the contact springs 3, 4are soldered together by means of a low-melting soldering metal-in suchmanner that these springs will spring apart When-the solder melts as aresult of a temperature higher than that permissible in the locality tobe controlled in which the thermocontact 'is placed. By these means areliable breaking of the contacts 3, 4 is secured, when the solderfuses. When the springs 3, 4 thus spring outwards they make contact withcontact pieces or wires 5, 6

so that a contact between the wires a, b is brought about on both sidesof the break. The melting of a thermocontact T consequently results in abreaking of both wires a, b and a contact between wires a, b ofdifferent signs on both sides of the break. Because the pieces 5, 6 bothhave the same function, there is double safety for really effecting acontact between the Wires (1, b.

The right-hand thermocontact T of section I diifers from thethermocontact just described substantially in this that one singlecontact piece or cross-conductor 1 is arranged on each side of thecontact springs 3, 4. The conductor 1 may consist of a simple metalliccross-piece secured to a pillar or plinth, around which the base plateof the thermocontact is cast or pressed.

The section relays Ra, Rb, RIIa, Bill) also have normally closedcontacts kv, kn. The contacts kin of relays Ra, Rm. and those of thesection relays of wires a of additional sections, if any, are connectedin series in a circuit from the pole of battery B1 through of contactskh, conductor I00, winding of normally energized alarm relay ARB- backto the pole of B. A similar circuit extends from the pole of battery B,through all the contacts lav in series, conductor 10!, winding ofnormally energized relay ARb to the pole of B.

A normally open alarm circuit extends from pole of battery B vianormally open contacts of relay ARb, conductor I03, fire alarm BS,conductor I02, contacts of relay ARa back to pole of B. The circuit isnot closed until both alarm relays ARa, ARb fall ofi simultaneously andclose their contacts.

When an alarm relay ARa, AB}; is de-energized and falls off, itscontacts also close an obvious circuit for a signal lamp ALE, ALb,respectively.

In addition to the devices shown, there may be provided the ordinaryswitches, signal lamps, signal bells, code wheels etc., as well-known inthe art; see for instance United States Patent No. 2,059,510. They formno part of this invention and are, for this reason, not shown. Thearrangement of the alarm relays and the fire alarm as shown herein isalso shown in said patent and forms no part of the present invention.

Reference is made to the fact that the arrangement of the sections I, IIand their connection with taps of the battery B is substantially shownand claimed in a United States Patent application (Serial Number184,100) by Olof Ingemar Harald Ekman and Hans Teodor Nicou. However,the sections may be arranged in any well-known or suitable manner, forinstance, as shown in United States Patent No. 2,059,510.

As described in said patent and patent specification, and as is evidentfrom the annexed drawings and the foregoing description, when a wire,say wire a of section I, is broken the corresponding section relay Ra isde-energized and released, breaking its contact kn. Thus the circuit foralarm relay ARB. is opened at Ru and that relay is released and closesits contacts. This closes the circuit for lamp ALa which is illuminatedand indicates the fault. But the circuit for the fire alarm BS remainsopen at the contacts of relay ARb. Similarly, if a wire b is broken, itssection relay, say Rb, is de-energized and releases ARb. If both a wirea and a wire b are broken simultaneously, both relays ARE, .ARb arereleased and close the circuit for the fire alarm BS so that alarm israised.

When both relays of a section, say Ra, Rb of section I, are thusde-energized in case of fire, the upper normally closed contacts of thepairs 11v, an, bv, bh are opened and the lower, normally open ones areclosed so that the milliamperemeters Av, Ah are connected with the wires(1, b of the section I broken. Then the circuits for the ammeters are asfollows:

(1) From pole of battery B2, through lower contact at bh, right-handpart of wire I) to the thermocontact broken (indicated by a brokenline), across to the wire b, back through righthand part of wire b,lower contact at an, amperemeter Ah to pole of B2.

(2) From pole of battery B1, through lower contact at bv left-hand partof wire b to the thermocontact broken, across to wire a, back throughleft-hand part of wire a, lower contact at av, amperemeter Av to pole ofB1.

Thus, the two amperemeters are automatical- 1y connected with thatsection, say I, which has been broken and now measure the intensities ofthe currents through the wires of different signs (a, b) connectedtogether, on both sides of the thermocontact broken. It is evident thatthese amperemeters, if properly graduated, directly indicate theposition of the break, for instance, by means of a code number or othermark. There are two circuits (1) and (2) above for indicating the break,giving double security. If, as a result of bad contacts at the springs3, 4 of the thermocontact fused, the two amperemeters show differentindications, the amperemeter giving the highest indication or deviationshould be followed.

Because a break of a section giving a high deviation of one amperemetergives a low deviation of the other, the amperemeters should, preferably,be graduated in opposite directions. By suitable reversion they may, ofcourse, be graduated in the same direction. The needles of theamperemeters may also be arranged co-axially on the same dial so thatthe needles register both normally and after a section has been broken.In case of difference, it is then easier to see which needle has thegreatest deviation. It is to be observed that a greater difierencebetween the deviations of the amperemeters indicates that severalthermocontacts are broken. Consequently, the amperemeters indicate thelimits of the spread of the fire.

In the plant shown the relays Ra, Rb, Rm, RIIb in the normal mannerindicate the sections in which a fault has occurred or from which alarmis given. In accordance with this invention the sections may be made fargreater than heretofore, without any inconveniences, because themilliamperemeters which are automatically cut in in case of alarm,directly localize and indicate that thermocontact which has been broken.For instance, the number of thermocontacts of a section may be increasedto or more. This is very advantageous. Because it is necessary to drawwires back to the central post say for each group of 100 thermocontactsonly, the total length of wire required is reduced, while simultaneouslythe indication is far more precise than in the systems heretofore known.The reduced length of wire-for the same total number ofthermocontacts-means lower costs of construction and lower risks offaults. Simultaneously the system has the highest degree of reliability,because alarm is certainly raised when two wires a, b are broken, andthe raising of alarm is independent of the local indication effected bythe amperemeters.

Referring now to Fig. 2 of thedrawings, condensers 9. are inserted.between.the wires a, b, one. condenser, being providedat each thermo-,contact. The condenser may be. placed on. either sideof thethermocontact. Preferably, the con-. denseris inserted into a recess ofthe base plate of ,the thermocontact, is soldered to the. termi-L nalsof the thermocontact and coated with a suitable solidifying mass,protecting. thecon-. denser against moistureetc.

In this embodiment, a source of alternating or pulsatory currentisprovided in the central postfor the milliamperemeters- In Fig. v2;.saidsourceis illustrated as current-breaking buzzers S sending a pulsatingcurrent through ,themilliamperemeters Av, Av, when the relays. .ofya.section, say Ra, Rb, are. released. simultaneously. But for the buzzerswith their batteries an inductor or a relay device or a mechanicallydriven switch which alternately charges and discharges a centralcondenser battery, may be substituted.

In the embodiment shown in Fig. 2 ordinary thermocontacts or fuses areusedwhich only are broken in case of fire but do not interconnect thewires a, b on both sides of the break, In other respects the plant shownin Fig. 2 is similar to that shown in Fig. 1 and corresponding partscarry the same reference characters. Also the operation is quitesimilar.

When a thermocontact is broken in the sys-. tem shown in Fig. 2, theamperemeters and their sources B1, S; B2, S of alternating orpulsatingcurrent-are automatically connected with the section, say I, containingthat thermocontact. As described in connection with Fig. 1, the lefthandamperemeter Av is connected with those parts of the wires a, b which areto the left of the broken contact T (indicated by abroken line). whilethe right-hand amperemeter Ah is connected with those parts of the samewires which are to the right of the broken contact. For each unbrokenthermocontactin theseleit and right parts a condenser 9 is insertedbetween the wires'a, b and lets through a partial or shunt currentbetween them. If the'condensers 9 are of approximately the same size andthe ohmic resistance of the wires may be neglected, this being quitepermissible if the wires are properly dimensioned, the amperemetersdirectly indicate the position of the broken thermocontact, because theintensity of the current is substantially proportional to the number ofcondensers in the left or right parts, respectively, and consequently tothe number of thermocoutacts between the measuring instrument Av, Ah andthe break.

Also in this embodiment the giving of alarm is quite independent of thecondensers 9 and the instruments Av, An. A break or a short-circuit in acondenser does neither put the system out of operation nor prevent alarmfrom being raised properly. A break in a condenser only has the effectthat in case of alarm the thermocontact next to that actually broken isindicated as broken, that is: the break only causes an indicationincorrect by a single step. A short-circuit within a condenser 9 isimmediately indicated by one of the section relays as an ordinaryshortcircuit or leakage between the wires, for instance, as described inU. S. Patent No. 2,059,510 or the U. S. patent application Serial No.184,100 referred to above.

In the plants shown in Figs. 1 and 2, it is possible to have anindication in accordance with the present invention, say for everysecond or every fifth thermocontactT. In such case,

only every second or fifth thermocontact has; a:

condenserS or cross-ccntact-making means 5,13, 1, while the remainingthermocontacts are; of the ordinary design without any condensers orcross-contacts.

In the plant shown in Fig. 2 the condensers may have graded sizesdependingupon their distance from. the central post, to compensate forthe ohmic resistance of the wires 0,, b.

In the embodiment shown, the amperemeters are automatically connectedwith wires a, b in case of alarm. Obviously, this may be mademanually'by use of switches or keys, instead of automatically. Allthermocontacts of .a whole plant may be included in one single section,indication by means of milliamperemeters being pro.- vided say for everytwentieth or thirtieth thermocontact. Such system has a very low cost ofconstruction and is in many cases sufficient. As a rule, however, it ispreferred to distribute the thermocontacts on several sections, saythermocontacts per section. Each section need not have its own sectionrelays in the central post; on the contrary the sections may beconnected in series, only two section relays being provided which arecommon to all sections. In the central post asuitable kellog-switch orthe like is provided for each section. When a fault occurs in a section,and is indicated, that section is disconnected from the other by use ofsaid switches and is connected with a special alarm relay common to allsections, while the remaining sections are still connected in series.

In this case suitable resistances of different sizes are inserted intothe sections at their both ends connected with the central post,rendering it possible to differentiate the sections and theirthermocontacts more easily by means of the ampererneters.

If the sections connected in series are con-. structed in accordancewith Fig. 2, the amperemeters will first indicate the section in which abreak occurs. After that section has been disconnected from the oth rsand is alone connected with the ampererneters, the latter will indicatethe position of the broken thermocontact within the section.

It is tobe observed that the plants as shown above do not include anymovable selectors or similar mechanical devices, this being favourablefor a high reliability. However, selectors or finders may be used forconnecting the amperemeters to the alarm-giving section.

This invention may also be applied to plants having one or more singlewire sections, the earth serving as a return path for the current. Foroperating the milliamperemeters parts of the central battery B may beused instead of the batteries B1, B2. Only one milliamperemeter may beused but two milliamperemeters give a double control and also anindication of the extension of the fire.

Reference is made to the fact that the plant shown in Fig. 2 has noadditional contacts to be closed in the thermocontacts in case of fire.For this reason the reliability is as high as possible.

It may be mentioned that this invention may very advantageously beapplied to ships and other structures comprising a great number of smalllocalities to be controlled. In such case the high localizing capacityof this system is of special importance, because the systems heretoforeknown cannot efiect such localizing of high ex-.

actitude, by means of devices economically possible.

If two sections simultaneously release alarm, which is improbable, thewatchman, seeing the lamps of two sections burning simultaneously, hasto connect the milliamperemeters manually with those sections one afterthe other to establish where the break is in each of those sections.But, of course, automatic means, such as relays, may also be used forconnecting the milliamperemeters with only one section at a time.

What I claim is:

1. In an automatic electric alarm system, in combination, a loop ofinsulated wires normally closed extending through the locality to bewatched over, current-breakers in said wires responsive to the cause ofdanger to be warned against, condensers connected at intervals be tweensaid wires, a source of current connected to said wires to delivercurrent to them, as long as they are unbroken, said current being of acharacter to which said condensers set a high resistance, a secondsource of current of sulficiently high frequency that said condensersset a comparatively low resistance to the flow of it, means forelectrically measuring the current from said second source, whenconnected to one end of said loop, after one of said current-breakers isopened, and an electric alarm mechanism connected to said wires to raisealarm, when one of said current-breakers is opened.

2. In an automatic electric alarm system, in combination, a battery fordirect current, a loop of insulated wires normally causing directsupervisory current and connected to said battery and extending throughthe locality to be watched over, current-breakers in said wiresresponsive to the cause of danger to be warned against, condensersconnected in parallel between said wires at intervals between saidcurrent-breakers, a source of pulsatory current for cooperating with oneend of said loop, said pulsatory current having sufiiciently highfrequency that even one of said condensers sets a comparatively lowresistance to said pulsatory current, means for measuring said pulsatorycurrent passing through one or more of said condensers, when one of saidourrent-breakers has been opened, and an electric alarm mechanismconnected to said wires to raise alarm, when one of saidcurrent-breakers is opened.

3. In an automatic electric alarm system, in combination, a loop ofinsulated wires normally closed and extending through the locality to bewatched over, current-breakers in said wires responsive to the cause ofdanger to be warned against, condensers connected at intervals betweensaid wires, a source of current connected to said wires to pass currentnormally through said wires, as long as they are unbroken, the currentdelivered by said source being of such a character that it issubstantially incapable of passing through said condensers, two sourcesof pulsatory current each for cooperating with one end of said loop,said pulsatory current being capable of passing through even one of saidcondensers with a low resistance, current-measuring means each connectedwith one of said two sources of pulsatory current for measuring thepulsatory currents through one or more of said condensers from both endsof said loop, when one of said current-breakers has been opened, andelectric alarm mechanism connected to said wires to raise alarm when oneof said currentbreakers is opened.

4. In an automatic electric alarm system, in combination, a loop ofinsulated wires normally closed and extending through the locality to bewatched over, current-breakers in said wires responsive to the cause ofdanger to be warned against, condensers connected in parallel atintervals between said wires, a source of current connected to saidwires to pass current normally through said wires as long as they areunbroken, the current delivered by said source being of such characterthat it is substantially incapable of passing through said condensers,normally closed section relays in said wires, an alarm apparatusconnected with said relays to raise alarm, when one of saidcurrent-breakers is opened and releases said relays, a second sourcepulsatory current connected with said relays to be connected with oneend of said loop when said relays are released, the current delivered bysaid second source of current being of sufiiciently high frequency thatit is capable of passing easily through one or more of said condensers,and means associated with said second source of current for measuringthe pulsatory current when said relays are released.

HANS TEODOR NICOU.

